The Center for AIDS Prevention Studies (CAPS) is committed to local, national, and international studies in primary and secondary prevention. We are proposing to continue our activities for a second five years, building on a strong track record of research publications and of involving minority scientists. Nine major research projects are included: HIV Prevention in High Risk Adolescents; AIDS Risk in Disadvantaged Black Adolescents in Housing Projects; Improving Physician's Sexual Risk Counseling; Methodology Studies; Coping, Mental Health, and HIV Risk Behavior in Black Men; Community Mobilization for Primary and Secondary Prevention; Adherence in Clinical Trials for HIV Disease; Preventing Heterosexual Transmission of HIV in Rwanda; Collaborative Studies in Developing Countries. Five cores serve these projects and the separately funded CAPS-affiliated projects of our investigators. The Administrative Core will lead, and the Scientific Theory and Methods Core will foster scientific productivity and rigor. The Ethics Core and Policy Core will address and publish the ethical and policy implications of our work; the Technology and Information Exchange Core will disseminate our work quickly to other scientists, to community-based organizations, and to the general population. CAPS provides an optimal setting for a diverse team of scientists to plan and carry out AIDS prevention research. We are interdisciplinary, combining critical groups within UCSF (behavioral medicine, epidemiology, medicine, survey research, biostatistics, social marketing, ethics and policy analysis) and within the San Francisco Community: Bayview-Hunter's Point Foundation (expertise in research and access to minority communities), San Francisco AIDS Foundation (experience in primary and secondary prevention programs), and Communication Technologies (experience in social marketing, diffusion theory, and survey research). CAPS maintains a rare and exclusive focus on AIDS prevention, brings theoretical and methodological rigor to this problem, has a commitment to multicultural inquiry, and provides an applied and community based perspective within a medical school setting.